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Author(s): Vattulainen, Jenni; Kajava, Sari; Heikkinen, Milja; Rinne, Marketta; Sairanen, Auvo Title: The effect of pelleted concentrate containing 3-NOP on methane emissions of dairy cows using separate vs. total mixed ration feeding Year: 2024 Version: Published version Copyright: The Author(s) 2024 Rights: CC BY-NC 4.0, other licences or copyright may apply to illustrations. Rights url: http://creativecommons.org/licenses/by-nc/4.0/ Please cite the original version: Vattulainen, J.; Kajava, S.; Heikkinen, M.; Rinne, M.; Sairanen, A. (2024). The effect of pelleted concentrate containing 3-NOP on methane emissions of dairy cows using separate vs. total mixed ration feeding. Pages 55-58. In Peter Udén (chief editor), Proceedings of the 12th Nordic Feed Science Conference, Uppsala, Sweden. https://doi.org/10.54612/a.4h6nuvh43i https://doi.org/10.54612/a.4h6nuvh43i Proceedings of the 12th Nordic Feed Science Conference, Uppsala, Sweden Swedish University of Agricultural Sciences, SLU Department of Applied Animal Science and Welfare Reports from department of applied animal science and welfare, no. 3 2024 June 18 - 19, 2024 Proceedings of the 12th Nordic Feed Science Conference, Uppsala, Sweden Proceedings of the 12th Nordic Feed Science Conference, Uppsala, Sweden Editors Peter Udén (chief editor) Torsten Eriksson Cecilia Kronqvist Rolf Spörndly Marketta Rinne Egil Prestløkken Horacio Gonda Pekka Huhtanen Martin Riis Weisbjerg Bengt-Ove Rustas Publisher: Swedish University of Agricultural Sciences, Department of Applied Animal Science and Welfare Year of publication: 2024 Place of publication: Uppsala Title of series: Reports from Department of Applied Animal Science And Welfare Part number: 3 ISSN (Print) 2004-9803 ISSN (Online): 2004-934X ISBN (print version): 978-91-8046-741-4 ISBN (digital version): 978-91-8046-742-1 DOI: https://doi.org/10.54612/a.4h6nuvh43i Keywords: Nordic Feed Science Conference © 2024 SLU This publication is licensed under CC BY NC 4.0, other licences or copyright may apply to illustrations. Foreword We are proud of the fact that this year, we can get together for the 12th conference in a row with only one year with Corona when we had to cancel. The future of the conference is, however, uncertain as the organizers are getting older and even retired. You are welcome to contact the organizers with ideas of how to proceed in coming years. We have received a total of 34 written contributions this year with the following distribution: 10 on Ruminant Nutrition, 6 on Conservation, 5 on Methods and Miscellaneous, 10 on Methane and 3 on plants. Climate change is serious threat to human and animal life and will also affect plant distribution and plant survival. Farmers will need to adapt and cultivate less familiar plant species to secure feed to their livestock in coming years. Three of the invited speakers to this conference, that we have been lucky to engage, will address climate change effects on future plant cultivation for ruminant feeding. Professor Édith Charbonneau from Université Laval, Québec, Canada will present consequences of climate change on milk production in Canada. Professor Karl-Heinz Südekum from the University of Bonn, Germany will talk about possible future forage production and livestock feeding in N. Europe. Swedish perspectives on forage plant resilience will be presented by Professor David Parsons from the Swedish University of Agricultural Sciences. A somewhat different talk in this conference will be given by author and Senior Consultant Gunnar Rundgren, Garden Earth, Sweden. The presentation will end this conference and compares the feed use and production of human edible food among Swedish livestock systems. We also want to take the opportunity to thank the main sponsor of the conference, Stiftelsen Seydlitz MP bolagen. You are all most welcome to the conference! For downloading proceedings of earlier conferences, please go to our homepage: https://www.slu.se/en/departments/department-of- applied-animal-science-and-welfare/conferences/nordic-feed-science-conference- 2024/proceedings/ Uppsala 2024-05-30 Peter Udén https://www.slu.se/en/departments/department-of-applied-animal-science-and-welfare/conferences/nordic-feed-science-conference-2024/proceedings/ https://www.slu.se/en/departments/department-of-applied-animal-science-and-welfare/conferences/nordic-feed-science-conference-2024/proceedings/ https://www.slu.se/en/departments/department-of-applied-animal-science-and-welfare/conferences/nordic-feed-science-conference-2024/proceedings/ Contents Forage plants Utilizing forage crops more resistant to extreme weathers and an overall warmer climate – nutritional perspectives for the Northern Europe ruminant livestock sector 5 K.-H. Südekum Resilience of forages to drought in Nordic countries 12 D. Parsons, M. Lindberg, J. Oliveira, V. Picasso & M. Halling Forage nutritive value of dual-use populations of Kernza Intermediate wheatgrass 25 V. D. Picasso & K. Olugbenle Methane emission Effects of two novel feed additives on enteric methane production of Nordic Red dairy cows 29 J. Vattulainen, A.R. Bayat, T. Stefanski, M. Rinne & I. Tapio The effect of the methane inhibitors nitrate and 3-NOP on enteric methane in dairy cow 32 J. Karlsson, C. Alvarez, M. Åkerlind & N. I. Nielsen Effect of dairy cows’ yield index on the effect of enteric methane reducing dietary treatments 35 G. Giagnoni, M. Maigaard, W. Wang, M. Johansen, P. Lund & M.R. Weisbjerg Thirty years of intensive research to reduce methane emissions – what has been achieved? 38 P. Huhtanen Harvesting frequency, grassland species and silage additive affects in vitro methane production from silage 45 K.V. Weiby, S.J. Krizsan, I. Dønnem, L. Østrem, M. Eknæs & H. Steinshamn Milk and methane production from dairy cows fed grass silage of different grassland species and harvest frequencies 48 K. V. Weiby, M. Eknæs, A. Schwarm, H. Steinshamn, K. A. Beauchemin, P. Lund, I. Schei & I. Dønnem 3-NOP reduces methane emissions more when used in total mixed ration than in separate feeding 51 J. Vattulainen, I. Tapio, N. Ayanfe, M. Rinne & A.R. Bayat The effect of pelleted concentrate containing 3-NOP on methane emissions of dairy cows using separate vs. total mixed ration feeding 55 J. Vattulainen, S. Kajava, M. Heikkinen, M. Rinne & A. Sairanen Enteric methane emissions from Norwegian Red dairy cows fed compound feeds differing in the level of local ingredients 59 K.S. Eikanger, M. Eknæs, I.J. Karlengen, J.K. Sommerseth, I. Schei & A. Kidane Methane emissions in Icelandic dairy herds. Improved prediction of methane by utilizing available farm management data 62 J.Kristjánsson, J. Sveinbjörnsson, G. Gísladóttir, Þ.Sveinsson & J. Gísladóttir Ruminant nutrition Climate adaptation of dairy farms in northern climate: a Canadian perspective 65 É. Charbonneau, S. Binggeli, G. Jégo, M.-N. Thivierge, S. Delmotte & V. Ouellet When optimization goals for forage harvest in a forage dominant feeding system are not achieved – consequences and preventive measures 73 J. Sveinbjörnsson Effect of rapeseed products in diets and iodine supply to dairy cows on iodine concentration in milk – a field study in ten Swedish dairy herds 76 M. Åkerlind, A.H. Gustafsson, C. Lindahl & M. Karlsson Effect of molybdenum in farm-grown feed and copper supply to dairy cows on copper concentration in milk, urine, faeces, hair and liver – a field study in 10 dairy herds 79 M. Åkerlind, I. Hansen, L. Stensson, T. Lundborg & C. Kronqvist Effect of particle size reduction by extrusion on intake and digestion of reed silage in dairy heifers 82 B.O. Rustas, H. Thelin & A. Kiessling Effects of silage particle size reduction on feed total tract retention time and magnesium absorption in dairy cows 85 S. Ali, B.O. Rustas & C. Kronqvist Effect of wilting and use of silage additive in grass silage on feed intake and milk production in Norwegian Red dairy cows 88 A. Kidane, M. Grøseth, L. Karlsson, H. Steinshamn, M. Johansen & E. Prestløkken Effect of restrictedly fermented grass silage on rumen metabolism and nitrogen utilisation 91 M. Grøseth, L. Karlsson, H. Steinshamn, M. Johansen, A. Kidane & E. Prestløkken Beef-on-dairy heifers grazing semi-natural grasslands can produce tender beef 94 A. H. Karlsson, F. F. Drachman, K. Wallin & M. Therkildsen Ruminal pH data analysis in lactating dairy cows fed with a SARA-inducing diet 97 Y. Shrestha, R. Danielsson, B-O. Rustas, S. Hägglund, J-F. Valarcher, T. Eriksson, M. Åkerlind & H. Gonda Conservation Effect of different additives and harvesting date on fermentation characteristics of maize silage 101 A. Milimonka, B. Hilgers, C. Schmidt & Y. Sun Field survey on the silage quality of Finnish farms 104 M. Franco, N. Ayanfe, A. Okkonen, A. Ellä & M. Rinne Effects of cultivars and additives on preservation quality and antinutritional factors of crimped ensiled faba bean seeds 107 N. Ayanfe, M. Franco & M. Rinne Grass for biorefinery: effect of additive treatment on fermentation quality of ensiled intact grass and pulp 110 N. Ayanfe, T. Stefański, T. Jalava & M. Rinne Examining the effect of silage inoculants containing only homo-fermentative or a combination of homo- and hetero-fermentative strains on fermentation of grass ensiled immediately after cutting or wilted for one day and rewetted by rain or one day wilted, rewetted by rain and wilted another day 113 I. Eisner, K. L. Witt & S. Ohl Vacuum storage of moist grain 116 M. Knicky & P. Mellin Miscellaneous Rate of NDF degradation from static measures 119 M.R. Weisbjerg & N.P. Hansen Residual weight loss of grass and grass-clover silages dried at 103°C after pre- drying at 60°C 122 N. B. Kristensen The use of feed in the Swedish livestock system 125 G. Rundgren Fish meal replacement with torula yeast (Cyberlindnera jadinii) and enzymatic treatment of the aquatic feed model can affect the flow resistance in the pelleting die and alter physical properties of the pellets 132 D.D. Miladinovic, C. Salas-Bringas, E.J. Mbuto, S. Pashupati & O.I. Lekang Body condition score of Icelandic dairy cows 136 J.Kristjánsson, J. Sveinbjörnsson & B.Ó. Óðinsdóttir Forage plants Proceedings of the 12th Nordic Feed Science Conference 5 Utilizing forage crops more resistant to extreme weathers and an overall warmer climate – nutritional perspectives for the Northern Europe ruminant livestock sector K.-H. Südekum University of Bonn, Institute of Animal Science, Endenicher Allee 15, 53115 Bonn, Germany. Correspondence: ksue@itw.uni-bonn.de Introduction Climate refers to the long-term (decades) pattern of several weather events or parameters that may be described on a regional basis. Weather is the present (daily, hourly or instantaneous) components of climate, including temperature, all forms of precipitation, relative humidity, wind and solar radiation. Forage species and plant populations can adjust or adapt physiologically and morphologically over a certain range of climatic variability (e.g. temperature and rainfall) to produce and persist (Baron and Bélanger, 2020). Thus, climate change has long-term effects, whereas extreme weathers have short-term effects and require short-term adaptation. Craine et al. (2013) studied global diversity of drought tolerance and grassland climate-change resilience of 426 grass species and concluded that “our findings suggest that diverse grasslands throughout the globe have the potential to be resilient to drought in the face of climate change through the local expansion of drought-tolerant species”. In line with this statement, model-based estimates for median seasonal above- ground timothy (Phleum pratense) grass yield on dairy farms in four regions of Norway (south-east, south-west, central and north) varied between 11,000 kg and 16,000 kg dry matter per hectare and was higher in all projected future (2046-2065) climate conditions than in the baseline (1961-1990) (Özkan Gülzari et al., 2017). The authors also emphasized that the uncertainty associated with future climate and decision making at farm level reflect that the implications of the future climate projections will vary from farm to farm. The uncertainty is further increased based on climate model indications that global warming through stimualion of atmospheric exchange processes will increase rainfall variability, leading to longer dry periods and more intense rainfall events (Walter et al., 2012). Recent studies suggest that both the magnitude of the rainfall events and their frequency may be as important for temperate grassland productivity as the annual sum. These phenomena may be of particular importance for the Nordic countries with their strong gradient in annual precipitation from the wetter (south-)west to the drier (north-)east (Skjelvåg, 1998). Most research on adjustment or adaptation of forage species or plant communities to climate change and extreme weathers has focused on (warm) arid and semi-arid regions and less on cold-humid areas. In the following passage, an attempt is made to briefly delineate nutritional perspectives for the Northern Europe ruminant sector in utilizing forage crops more resistant to extreme weathers and climate change with some general considerations, after which forage grass and legume species are separately addressed. General Considerations It is generally assumed that increasing temperature and elevated carbon dioxide (eCO2) have positive effects on forage yield in northern Europe (Liu et al., 2023). Although this sounds promising, a more specific look at boreal regions generates a complex picture. Ergon et al. (2018) have reviewed climate change and its effects on grassland productivity across Europe and shown that the Nordic regions are facing increasingly warmer and wetter winters, such that – at a first glance – warming and eCO2 may boost forage production in the Nordic region due to an extended growing season. These effects may however be balanced or even Forage plants 6 Proceedings of the 12th Nordic Feed Science Conference overcompensated by more winter thaws and less snow cover along with more summer drought events, which may reduce winter survival and summer regrowth, thus potentially reducing the persistence of perennial forages over time (Thivierge et al. 2023). It also appears that benefits of an extended growing season can only be utilized when impacts on forage quality and the altered annual productivity cycles are counterbalanced with adequate adaptations in defoliation and fertilization strategies. The identity of species and mixtures with optimal performance is likely to shift somewhat in response to altered climate and management systems. It is argued that breeding of grassland species should aim: (i) improve plant strategies to cope with relevant abiotic stresses and (ii) optimize growth and phenology to new seasonal variation, and that plant diversity at all levels is a good adaptation strategy (Ergon et al., 2018). Based on nearly two decades of research on the effects of climate change on forages in cold and humid areas of northeastern North America, Thivierge et al. (2023) have evaluated and summarized the expected effects of climate change on forage production in terms of yield, nutritive value, and winter survival. The authors have also proposed a set of 12 adaptation and resilience-building strategies for forage systems that can be implemented at the field and farm levels to which the interested reader is referred. Selected aspects from this comprehensive review, particularly those related to changes in forage yield and quality, are briefly summarized in the following paragraph as they address both, grass and legume species: “The positive yield response to atmospheric eCO2 concentration is generally greater in legumes than in grasses, due to the N-fixing ability of legumes. The increased plant demand for N under eCO2 often limits growth while biological N fixation in legumes, is enhanced at eCO2 as a response to low soil-N availability. Without any adaptation to the harvest schedule, climate change is then expected to reduce forage nutritive value, although this effect will depend on the species. Drought will also affect plant species differently. As a drought sensitive species, timothy (Phleum pratense L.) is expected to suffer from more frequent and intense water stress events, with reduced summer regrowth. Without any adjustment to the harvest schedule of timothy, its nutritive value (averaged across five sites in eastern Canada) is expected to decrease through increased neutral detergent fibre (NDF) concentration and decreased in vitro NDF digestibility (dNDF) for the first and second harvests, respectively. This projected negative effect on the nutritive value of timothy is in line with experimental results that showed a reduction in dNDF of timothy with increasing air temperatures. Alfalfa (Medicago sativa L., also called lucerne) is not only expected to have a greater positive yield response to atmospheric eCO2 concentration than most grasses but is likely also less affected than timothy by water stress under future climate conditions in eastern Canada. When climate conditions are less suitable for alfalfa growth, a yield increase was projected by mid-century for another legume–grass mixture composed of white clover, red clover and timothy.” Grass Species (C3 grasses) Grass species in natural or sown pastures in boreal regions are all C3 grasses and, although the general expectation is that they will benefit in terms of biomass yield from a longer vegetation period caused by climate change, the observed or projected effects of increased inter-annual precipitation, i.e., rainfall, variability on forage yield and quality are variable and sometimes contradictory. Of the two extreme rainfall variabilities, drought has been studied Forage plants Proceedings of the 12th Nordic Feed Science Conference 7 more often in terms of forage yield and quality than excessive rainfall with long-lasting wet conditions and the former aspect will thus be addressed in the following. However, heavy rainfall, often accompanied by low temperatures, during the growing season also affects plant biomass accumulation and composition but, more severly, may not allow crops to be harvested, demanding that alternative feed resources, sometimes called ermergency feeds, such as wood products, are considered and evaluated. This aspect has been addressed, e.g., at the 10th Nordic Feed Science Conference (Prestløkken & Harstad, 2019; Rinne & Kuoppala, 2019) and, notwithstanding its periodic relevance, will not be covered here. Bērziņš et al. (2019) assessed the total dry matter yield and regrowth capacity of seven grass species in 2018, the driest year in the history of Latvian weather observations with extreme drought durig the summer. The grass species in the field experiment ranked in the following descending drought resistance sequence: Tall fescue (Lolium arundinaceum (Schreb.) Darbysh., formerly Festuca arundinacea Schreb.) > red fescue (F. rubra); > orchard grass (also called cocksfoot, Dactylis glomerata) > timothy (P. pratense > meadow fescue (F. pratensis) > festulolium (xFestulolium) > perennial ryegrass (Lolium perenne). Fariaszewska et al. (2020) examined yield and quality traits of nine forage grass varieties belonging to Festuca, Lolium and Festulolium under mild drought stress conditions in a semi-controlled field experiment. Dry matter yield was significantly lower in drought stress than under control conditions and the physiological parameters reacted within 2 weeks after start of the drought treatment in all species. In contrast, drought stress significantly increased water use efficiency, the content of proline, phenolic acids, flavonoids, water soluble carbohydrates and decreased neutral and acid detergent fibre on both years. Based on total dry matter yield, Italian rygrass (L. multiflorum) ranked highest in the first and tall fescue in the second investigated year. Grant et al. (2014) presented data from a field experiment in which a temperate European grassland was subjected to altered intra-annual precipitation variability (low, medium, high) in interaction with management strategies namely fertilization and alteration of harvest date (delay by 10 days). Increased intra-annual precipitation variability decreased forage yield of the grassland. Furthermore, proportion of functional groups was altered toward less grass and more forb biomass with amplified precipitation variability. Increased crude protein content and reduced fibre content with increasing precipitation variability improved relative feed values. On the contrary, McGranahan & Yurkonis (2018), in a study conducted in North Dakota, USA, found that, although grasses (C3 and C4) increased forage quality and quantity under eCO2 concentrations, forage quality and quantity of C3 grasses declined under simulated drought. Crude protein content was enhanced by fertilization during drought but was reduced by delayed harvest after the drought period. Similarly, Carlsson et al. (2017) showed that sward resistance and resilience to drought stress were increased by nitrogen fertilization. Because morphological and nutritional adjustments within plants in response to warming and drought vary among species and less is known how these relate to production and forage quality, Catunda et al. (2022) grew two common pasture species, tall fescue and alfalfa in a climate-controlled facility, under different temperatures (ambient and elevated) and watering regimes (well-watered and droughted). They found that drought had a strong negative impact on biomass production, morphology and nutritional quality while warming only significantly affected both species when response metrics were considered in a multivariate principal component analysis, although to a lesser degree than the drought. Catunda et al. (2022) Forage plants 8 Proceedings of the 12th Nordic Feed Science Conference concluded that in future climate scenarios, drought may be a stronger driver of changes in the morphology and nutritional composition of pasture grasses and legumes, compared to modest levels of warming. The potential of orchard grass performance and in particular, nutritive value, under a combined climate-change (increased temperature and eCO2 concentration) and water stress (drought) scenario was studied by Küsters et al. (2021a, b) in an alpine environment in Austria. The combination of increased temperature and eCO2 concentrations lead to an increased and accelerated conversion of non-protein-N compounds into complex protein compounds. Simultaneously, it accounted for increased proportions of water-soluble carbohydrates (WSC), and higher WSC is connected to increased digestibility and metabolizable energy contents. Height and weight of plants decreased under elevated temperature and eCO2 in the second and third cuts. Under increased temperature and eCO2,orchard grass accumulates certain nutrients while a decline in tiller growth in the second and third growth is likely. This observation on orchard grass is not at odds with reports from the in northeastern United States (reviewed by Thivierge et al., 2023) that yield is expected to remain stable or to decrease. In the seond study, Küsters et al. (2021b) observed that, besides elevated temperature and eCO2, impact of water stress can be severe on the performance of orchard grass and its nutritive value. Water stress has improved valuable nutritive characteristics like WSC, crude protein and ME. Consequently, restrictive water supply is leading to an accumulation of specific nutrients, hence improving the nutritive value but with a prospective decline in biomass production. The authors concluded that consequences of drought conditions are mostly overcome in orchard grass as soon as the precipitation achieves its normal expected values for the specific season. Legume species Already more than 30 years ago, Peterson et al. (1992) determined effects of drought on herbage yield and quality and stand persistence of birdsfoot trefoil (Lotus comiculatus L.), cicer milkvetch (Astragalus cicer L.), red clover (Trifolium pratense L.) and alfalfa. Legumes were subjected to two soil water regimes promoting 'droughted' and 'well-watered' plant growth. Average herbage yield of droughted alfalfa was 120% greater than yields of birdsfoot trefoil and cicer milkvetch, and 165% greater than red clover yield. Droughted alternative legumes produced herbage with lower fibre concentrations than alfalfa. Improved quality in droughted legumes was related to greater leaf:stem weight ratio, delayed maturity, and often higher quality in both the leaf and stem fractions compared to the control treatment. Although drought reduced herbage yield of all legumes, alfalfa had the greatest yield potential under drought, albeit at a lower nutritive value. About 20 years later, an experiment on the effect of water shortage on the nutritive value of legume species was conducted by Küchenmeister et al. (2013). They examined effects of drought on crude protein fibre and WSC concentration of six legumes, namely birdsfoot trefoil, marsh birdsfoot trefoil (L. uliginosus Schkuhr); black medic (M. lupulina L.); yellow alfalfa (M. falcata L.); sainfoin (Onobrychis viciifolia Scop.) and white clover (T. repens L.) in monoculture and in mixture with perennial ryegrass in a container experiment in a vegetation hall. Moderate and strong drought stress was applied during three periods in two years. Effect of drought on nutritive values was considerably less pronounced than on yield. Forage plants Proceedings of the 12th Nordic Feed Science Conference 9 While the impact of moderate stress on nutritive quality was negligible, Küchenmeister et al. (2013) found a decrease in crude protein and fibre fractions and increased WSC under strong stress. This may indicate that water scarcity could even increase forage quality and digestibility. However, the choice of legume species and stand (monoculture or mixture) had stronger effects on nutritive values than drought. Küchenmeister et al. (2013) concluded that the influence of temporary drought on nutritive value characterstics seems to be less important for the selection of suitable forage legumes species than other agronomic properties under conditions of climate change. An interesting facet to alfalfa quality was reported by Pecetti et al. (2017) who investigated three alfalfa populations divergently selected for higher leaf-to-stem ratio, multifoliolate leaves or short-internode stems in four managed environments. Their results suggested that environmental effects might have greater impact on quality than genetic effects, even for a population set including material selected for quality-driven morphology. This can be taken as a subtle hint that adaptation measures in forage production and management in response to climate change and weather extremes are at least as important as selection of appropriate varieties within a given species. Maize Maize (Zea mays L.) is a C4 grass which is typically grown in warmer climates but also has a long history even in Nordic countries. Already Virtanen (1938) has documented research interest towards maize production in Finland, but the field area used for forage maize production in boreal European regions has remained low (according to official statistics from, e.g., Sweden and Estonia). Both climate change and more droughts during the vegetation period have revived efforts to cultivate forage maize in boreal regions. These efforts may receive additional incentive from a recent study conducted in northern Germany (Taube et al., 2020). Based on reports that yield increases in forage maize in northwestern Europe over time are well documented, they stated that the driving causes for these, however, remain unclear as there is little information available regarding the role of plant traits triggering this yield progress. Ten different hybrids from the same maturity group, which have typically been cultivated in Northwest Germany from 1970 to recent and are thus representing breeding progress, over four decades, were then selected for a 2-year field study in northern Germany. Based on the results of their study, Taube et al. (2020) concluded that the observed increase in silage yield in northwestern Europe can largely be explained through the increased temperature sum during the vegetation period of maize crops and the resulting earlier maturity in the last four decades. These increased temperatures have a direct effect on yield, as shown by results from a simulation model (MaisProg). Apart from this direct effect, the increased temperature also indirectly contributed to the higher yield through the selection or breeding of maize varieties with an increased leaf area index (higher number of leaves and longer leaves), a higher radiation use efficiency and a generally lower leaf angle. The study showed an annual progress, mainly driven by these plant traits, of about 130 kg DM/ha. The N efficiency of newer hybrids was also higher compared with older ones while overall forage quality was not affected. Future selection and adaptation of maize hybrids to changing environmental conditions are likely to be the key for high productivity and quality and for the economic viability of maize growing and expansion in Northern Europe. Lehtilä et al. (2024) stated that the cultivation of whole crop forage maize for cattle feed has a potential for increased forage yield while reducing N fertilization compared to perennial Forage plants 10 Proceedings of the 12th Nordic Feed Science Conference grass-based systems. The aim of their study was to compare the environmental impact of forage maize with more widely cultivated forage crops in Finland that included perennial silage grass mixtures and whole crop spring cereal harvested as silage. The use of plastic mulch film in forage maize cultivation was included in the assessment as well. A life cycle assessment was conducted and the overall conclusion was that forage maize could be used to supplement perennial grass cultivation without major associated environmental risks. Future research shall be conducted on the effect of forage choices on the environmental impact of boreal dairy milk production and on decreasing the current high uncertainty associated with nitrous oxide emission factors and soil organic carbon stock modelling choices. Conclusions Climate change has long-term effects, allowing plant communities and individual species to adapt in different ways. Extreme weathers have short-term effects and require short-term adaptation. Of overriding importance is that plant species must (1) survive and (2) perform under more extreme stress situations. Only if these two aspects are secured, forage quality can be addressed and modifications may come into effect through adapted and optimized forage management ranging from species selection (if applicable) and cultivation to harvest and preservation. References Baron, V.S. & Bélanger, G., 2020. Climate, climate-change and forage adaptation, in: Moore, K.J., Collins, M., Nelson, C.J., Redfearn, D.D. 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Feeds for ruminants from forests? in: Udén, P., Eriksson, T., Spörndly, R., Rustas, B.-O., Karlsson, J., (Eds.), Proc. 10th Nordic Feed Sci. Conf., Uppsala, Sweden. Report 302. Departm. Anim. Nutr. Managm., Swedish Univ. Agric. Sci., Uppsala, Sweden, pp. 79-86. Skjelvåg, A.O., 1998. Climatic conditions for crop production in Nordic countries. Agric. Food Sci. Finl. 7, 149-160. Taube, F., Vogeler, I., Kluß,C., Herrmann, A., Hasler, M., Rath, J., Loges, R. & Malisch, C.S., 2020. Yield progress of forage maize in NW Europe – breeding progress or climate change effects. Front. Plant Sci. 11, 1214. Thivierge, M.-N., Bélanger, G., Jégo, G., Delmotte, S., Rotz, C.A. & Charbonneau, É., 2023. Perennial forages in cold-humid areas: Adaptation and resilience-building strategies towards climate change. Agron. J. 115, 1519-1542. Virtanen, A.I., 1938. Kokemuksia maissin ja maissi-peluskin viljelyksestä maassamme [Experiences of maize cultivation in our country]. Karjatalous14, 243-253. Walter, J., Grant, K., Beierkuhnlein, C., Kreyling, J., Weber, M. & Jentsch, A., 2012. Increased rainfall variability reduces biomass and forage quality of temperate grassland largely independent of mowing frequency. Agric. Ecosyst. Environ. 148, 1-10. Forage plants 12 Proceedings of the 12th Nordic Feed Science Conference Resilience of forages to drought in Nordic countries D. Parsons1, M. Lindberg2, J. Oliveira1, V. Picasso3 & M. Halling2 1Swedish University of Agricultural Sciences (SLU), Department of Crop Production Ecology, 901 83 Umeå. 2Swedish University of Agricultural Sciences (SLU), Department of Crop Production Ecology, 750 07 Uppsala. 3Department of Plant & Agroecosystem Sciences, University of Wisconsin, Moore Hall, 53706 Madison WI, USA. Correspondence: david.parsons@slu.se Climate change and forages Global average temperatures have increased 1.4°C above the average of 1850-1900 (World Meteorological Organization, 2024) with the recent period between 2015-2023 having the warmest 9 years on record. The WMO also expects an increased frequency of extreme weather events such as drought and extreme heat. In Northern Europe, climate change is increasing the frequency and intensity of both droughts and excessive rainfall (IPCC, 2012, Strandberg 2015), which challenges forage production and the industries that rely on it. Various studies have examined the potential effects of climate change on forages. Climate change scenarios for Nordic and Baltic countries 2040- 2065 (Höglind et al., 2013) predict increased growing season temperatures, increased evapotranspiration (ET), and increased precipitation for most sites. Compared to the reference period (1960-1990) the projected future dry matter yields of timothy (Phleum pratense) were 11% greater, largely due to an increase in the length of the growing season. The optimal time for the first harvest was 8-20 days earlier than the reference period and an additional harvest could be taken at all sites. A study in Norway using climate projections (until 2099) combined with a simulation model (Persson and Höglind, 2014) found that timothy yields will increase at sites all over Norway. This was caused by increasing temperature, precipitation, and number of cuts during the growing season. However, the biomass could be more difficult to harvest at some sites due to shorter dry periods and high precipitation. Grusson et al. (2021) specifically examined the potential effect on agriculture in southern Sweden using different climate models and the SWAT soil water tool. The results suggest that although climate models may project increased rainfall, this will not lead to an increase in soil water content, firstly because increased rainfall is associated with heavy rainfall events that lead to increased runoff, and secondly because increased temperature increases transpiration. Regardless of whether water deficits will occur more frequently in the future, they are a part of the current reality. The year 2018 in Northern Europe was one of the harshest and widespread droughts in recent memory and caused yield losses far above normal levels (Beillouin et al., 2020) with dire consequences. In Sweden, the drought caused historic cereal yield losses and livestock number reductions due to lack of feed (Statistiska Meddelanden, 2018). Cattle farmers resorted to using a variety of alternative unconventional feed sources (Bergkvist and Spörndly, 2019) and some farmers were forced to emergency slaughter cattle, leading to widespread mainstream news coverage. This event substantially increased awareness of the devastating effects that droughts can have, particularly for producers of ruminants, and provoked a widespread debate about climate change and the potential effect on agricultural production in the future. Forage plants Proceedings of the 12th Nordic Feed Science Conference 13 While climate change might bring some benefits to forage producers in the Nordic countries, it comes with risks of future droughts. To adapt and thrive during the climate of the future, it is crucial to have access to forage crops which can both produce well in typical years (stability) and under water limitations (resilience). Defining drought The World meteorological organization (World Meteorological Organization, 2010) acknowledges that what might be drought in one area may not be drought in another, because drought is relative to the average conditions in that area. There are many ways to define meteorological drought, all with their strengths and weaknesses. For example, Mooley and Parthasarathy (1982) defined the severity of a drought through dividing actual rainfall by average rainfall and dividing the result by the standard variation. The standardized precipitation index (SPI) (Mckee et al., 1993) is based on precipitation only, which makes it easily usable from widely available weather data. It is a continuous statistical method which compares rainfall variability to historic rainfall. The Standardized Precipitation Evapotranspiration Index (SPEI) (Vicente-Serrano et al., 2010) takes both precipitation and evapotranspiration (ET) into account, which leads to a more robust measurement, but requires a method to estimate ET, either directly or through a model. An important distinction is between a drought and water limitations. For agricultural purposes, a shortage of water for plant growth doesn’t necessarily mean that there is a drought, however in this paper we will use the word drought more generally. Defining terms There are many terms related to agroecosystem performance, and they are used inconsistently, often causing confusion. Grimm and Wissel (1997), Death (2024), and Picasso et al., (2019) have good summaries of the terms, and their potential meanings. For the purpose of this paper, we will use terms in the following way, according to Sanford et al., (2021): Resistance – the ability to stay unchanged in the presence of a disturbance. Recovery – the ability to return to normal after a disturbance. Resilience – the combination of both resistance and recover. Stability – the ability to remain unchanged in the face of normal variability. Cropping systems with stability reduce uncertainty and risk due to less variability in yield from one year to the next. Resilient cropping systems remain relatively productive through a climatic crisis (e.g., drought), providing a buffer in the face of extreme weather (Sanford et al., 2021; Urruty et al., 2016). Definitions are also complicated and inconsistent when discussing the ability of plants to respond to water limitations. We will use the following terms: Drought resistance – the ability of plants to maintain normal physiological functions and growth, even when exposed to water limitations. Drought avoidance – the ability of plants to avoid water scarcity through adjusting their growth and development. Forage plants 14 Proceedings of the 12th Nordic Feed Science Conference Drought recovery – the ability of plants to recover normal function after a period of water scarcity. Drought resilience – a more general term including resistance, avoidance, and recovery. The mechanisms for drought resistance are complex and vary between species but can include osmotic adjustment, plant growth regulation, stress responsive proteins and antioxidant scavenging defence systems (Aslam et al., 2015). For forages in Northern Europe, the most important mechanisms of drought avoidance are variations in root morphology and depth. Deep roots enable plants to access water from lower in the soil profile, potentially avoiding dehydration. Alternatively, a spreading root system can explore more of the soil volume. The mechanisms of drought recovery are less clear. Plant breeding has traditionally focused on mostly yield, while drought resilience breeding has been less common (Tardieu et al., 2018). Drought effect on forage quality A review by Wang and Frei (2011) summarised that for forage crops there is a general pattern of increased protein concentration and digestibility during drought. In a meta-analysis of nineteen studies (Dumont et al., 2015) water stress led to an average increase of 5% crude protein, a decrease of 3% in neutral detergent fibre concentration, and more variable effects on digestibility. There are various potential reasons for a potential positive effect of drought on forage quality. Drought stressed plants may have higher leaf to stem ratios (Peterson et al., 1992) and reduced lignin concentration (Peterson et al., 1992; Petit et al., 1992). However, this can depends on the extent of the water stress, which in extreme situations can reduce leaf mass through accelerated senescence of older leaves (Buxton and Fales, 2015). Another reason for potential improved forage quality is that water stress delays the maturation of forages (Halim et al., 1989). This means that if the water stress is not too severe then the forage quality may be better in comparison with unstressed forage of the same age (Buxton, 1996). For example, a glasshouse study (Staniak, 2016) found that after a prolonged period of low soil moisture the maturity of the forage grasses were delayed by the drought stress, leading to higher protein concentrations and lower concentrations of crude fibre, but at the expense of decreased yield (31%) compared with the control. Such results are not consistent. For example, Küchenmeister et al. (2014) found no significant effect on any nutritive quality, including protein, between control and drought conditions, as long as the botanical composition was consistent. In a separate study, Küchenmeister et al. (2013) artificially induced drought stress in a range of perennial forage legumes. The results were variable, and the most significant finding was that drought stress has a stronger effect on yield than on nutritive value. A suggested reason for a potential increase in protein concentration during moderate drought is an increasing legume content of the sward, for reasons described below. The results are variable and depend on the extent of the water limitation and the drought resilience of the legume species. For forages, which have experienced moderate to severe drought, it is mainly the yield that is of concern, as most studies agree that quality factors such as protein and digestibility either are comparatively better or similar if the harvest date is kept the same. However, if farmers Forage plants Proceedings of the 12th Nordic Feed Science Conference 15 delay harvesting after drought to aim to achieve a typical level of yield, it is possible that they will end up harvesting forage of lower quality. Drought recovery The recovery phase of forage plants can be slow, and quite different between species. For example, in a study in Switzerland of simulated summer drought (Deléglise et al., 2015), the plants did not recover fully until the following spring. Post-drought stressed mixed grass and legume swards in Switzerland showed that grasses over-yielded by 52% in the regrowth compared to the control, whereas the legume did not respond in the same way (Hofer et al., 2017). In a pot experiment study (Staniak, 2016) forage grasses were grown in monocultures and either subjected to a simulated summer drought or were grown in optimal conditions. During drought conditions, the yields were reduced by an average of 31% compared to the irrigated control, however during the next year the grasses managed to overcompensate and had yields that exceeded the control group by an average of 7.5%. A suggested reason for post-drought over-yielding is the “Birch effect” (Birch, 1964). The Birch effect is the rapid mineralization of nitrogen when a dry soil becomes wet. The Birch effect may in part be responsible for the over-yielding of forage swards following a drought. The Birch effect may also explain why forage grasses, and not legumes, have a strong post- drought growth response, because grasses do not fix atmospheric nitrogen and are thus more sensitive to soil nitrogen availability and responsive to nitrogen fertilization. This hypothesis could be tested by supplying both drought-recovering and control plants with optimal nitrogen levels. Beyond the differences between grasses and legumes, there is little information on differences among or within species focusing specifically on drought recovery. Grass species comparisons In many studies comparing forage species for drought resilience there is no distinction between drought resistance and drought avoidance, and usually the methods used do not enable a distinction. In practice, it may not matter whether plants are more resilient because of resistance or avoidance – resilience is likely to be a function of multiple traits. The following section will summarise some research comparing the drought resilience of different forage species. There are fewer studies on drought tolerance in the Nordic countries in comparison with other stresses, such as cold and ice damage. The main perennial forage grasses used in Sweden are timothy, meadow fescue (Festuca pratensis), tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne), typically grown in polyculture with legumes. Of these species, only tall fescue is recognised as drought tolerant (Cherney et al., 2020). In a Danish field experiment (Kørup et al., 2018) different grass species and cultivars were grown in lysimeters in order to evaluate their biomass production and water use efficiency during and after drought stress. One cultivar of Cocksfoot (Dactylis glomerata cv. ‘Sevenop’) and two varieties of tall fescue (cvs. ‘Jordane’ and ‘Kora’) gave the greatest yields during both control conditions and during drought. A different cultivar of Cocksfoot (cv. “Amba”) and a cultivar of festulolium (x Festulolium cv. Hykor) had the lowest yield reduction (i.e. the yield in relation to the control yield). A lower yield reduction is likely due to lower pre- Forage plants 16 Proceedings of the 12th Nordic Feed Science Conference drought yields leading to greater water availability at the onset of drought. Not all festuloliums were drought tolerant. Two Festulolium cultivars originating from crosses between meadow fescue and perennial ryegrass were sensitive to drought. The study also found that some commercial cultivars which have not been specifically bred to be drought tolerant still exhibit drought resilience traits. The authors theorized that this has occurred during selection for yield in outdoor trials during drought years which will then select for drought resilience indirectly. Some grass species have different ploidy levels, which can have various effects on the phenotypic response. One study (Akinroluyo et al., 2020) researched the effect of ploidy level in Westerwolds ryegrass (Lolium multiflorum ssp. multiflorum) on drought resilience. Diploid cultivars and induced autotetraploids were compared in mild drought conditions. While autotetraploids produced more biomass during non-drought conditions the difference was significantly greater during drought conditions because they produced more phenolic compounds and had significantly higher antiradical activity. An experiment (Kemesyte et al., 2017) with perennial ryegrass showed similar results – the tetraploid perennial ryegrass outperformed the diploid variant under drought stress conditions. An early study with tall fescue (Burch and Johns, 1978) found that it has characteristics of drought avoidance, through a deep root system, and drought resistance, through stomatal control and dehydration tolerance. Tall fescue also has potential for its drought tolerance to be improved even further (Waldron et al., 2021). Resilience to drought had a moderately high heritability and the authors predict that it can be increased by 2.7% to 3.1% per selection. During the drought year 2018, the average of total seasonal dry matter yield over three sites from pure stand of species in forage variety trials in South and Middle Sweden were compared with year 2015, representing good rainfall (Halling, 2020). For first year leys, tall fescue had 60% of the 2015 yield, compared with 57% for meadow fescue, 66% for perennial ryegrass, and 54% for timothy. However, for second year leys, tall fescue had 72% of the 2015 yield, compared with 59% for meadow fescue, 59% for perennial ryegrass, and 65% for timothy. This confirms the drought resilience of tall fescue, but also that it is a slow species to establish, and its drought resilience is not fully developed in the first production year. Legume species comparisons In the Halling (2020) study, first year lucerne (Medicago sativa) had a relatively low percentage yield (45%), higher than white clover (Trifolium repens) (40%) but lower than red clover (Trifolium pratense) (64%). However, by the second year lucerne had a very high percentage yield (85%), compared to red clover (57%) and white clover (22%). The results confirm that white clover is drought sensitive and that lucerne is resilient once it has had sufficient time to become established. Küchenmeister et al. (2013) compared drought resilience of a range of legume species and found that yield reduction depended on the strength and duration of stress. However, the study focused on forage quality and there was no statistical analysis of yield data. Komainda et al. (2019) compared drought resilience of white clover to birdsfoot trefoil (Lotus corniculatus), yellow lucerne (Medicago falcata), black medic (Medicago lupulina), and common sainfon (Onobrychis viciifolia) monocultures in controlled environment conditions. Black medic and birdsfoot trefoil had the lowest relative reduction in yield, whereas white clover had the greatest. However, white clover still had a similar level to black Forage plants Proceedings of the 12th Nordic Feed Science Conference 17 medic and birdsfoot trefoil under drought stress. Because this was a controlled environment experiment with limited space for roots to explore, it is likely that the species had similar yields under drought conditions because all species used up the limited available water. It is unclear how these results would transfer to field conditions. Deep rooting is one of the major mechanisms of drought avoidance. In a set of experiments in Switzerland and Ireland, Hofer et al. (2016) compared monocultures of white and red clover in a simulated summer drought experiment. Red clover was consistently higher yielding than white clover in both control and drought conditions. The yield reduction due to drought was similar for the two species. The authors conclude that the ‘deep rooting’ trait might contribute to drought resistance, but that the effect could be small and might become important only under extreme drought conditions. Another study in Switzerland (Prechsl et al., 2014) found that contrary to expectation, grasslands under drought conditions did not exhibit a strong increase in water uptake from deep in the soil. This was observed in mixed swards and it is unclear if these results can be generalized. Lucerne is well-known to be a drought resilient species, but few published articles in Northern Europe have compared its performance in detail with other species. In a pot experiment, Norton et al. (2021) compared water use of white clover and lucerne during a drying cycle. They found that white clover used a greater proportion of the soil water, likely due to its more branched and finer root system. Lucerne used water more conservatively, allowing it to survive longer during the drying cycle. Lucerne also partitioned more of its energy into root growth, maintained a higher relative water content, and had higher water use efficiency. The experiment did not address the potential for lucerne to access deep water, due to the limitations of the pot volume. Even within the species, there are differences between lucerne cultivars. Picasso et al., (2019) found that US cultivars of lucerne differ in resilience to drought, stability, and productivity. Cultivar stability was not associated with productivity, and it was negatively associated with disease resistance. Cultivar resilience was negatively associated with productivity, and not associated with other traits. With increasing year of release of cultivar, cultivar productivity increased, stability was not changed, and resilience decreased. In the Czech Republic, Hakl et al., (2019) also found that stability and productivity of lucerne cultivars were not related. These studies highlight the importance of maintaining resilience in new cultivars, and not having productivity as the only breeding goal. Sward mixtures and diversity Küchenmeister et al. (2014) compared the response of monocultures and mixtures to drought, in a controlled environment. On average, yield was reduced by 12% with moderate drought stress, with the worst performing sward reduced by 22% compared to the control, demonstrating that sward composition had a significant effect. Importantly, functional group diversity (legumes, grasses and forbs) was more important than the number of species. The importance of functional groups was confirmed by Komainda et al. (2020). They found that swards performing at the maximum level could be achieved with as few as 3 species (although a maximum of 5 species were used and the options were limited), as long as functional diversity was high. This is likely because functional group diversity is the surest way of increasing functional trait diversity, where traits include factors such as rooting depth, nitrogen fixation and speed of phenological development. It is important not to generalise the “optimal” number of species, because this may depend on the conditions. The Komainda et Forage plants 18 Proceedings of the 12th Nordic Feed Science Conference al. (2020) study only included one type of legume (white clover). Most studies do not include multiple sites, years, stress events, soil types, etc., and we hypothesize that swards with greater species diversity have potential to be more resilient across diverse environments. A specific reason to combine legumes and grasses in swards is that legumes can fix atmospheric nitrogen. This gives legumes an advantage over grasses in low nitrogen conditions, such as occur during drought where lack of water also makes nitrogen less accessible. In practice, this can lead to greater water use efficiency for legumes than grasses, as demonstrated with lucerne in New Zealand (Moot et al., 2008). Hofer et al. (2017) found that legumes had an advantage over grasses during drought, due to their nitrogen fixation, whereas grasses were able to overcompensate during post-drought recovery. This confirms that mixtures of legumes and grasses can provide a more stable yield during and after drought. Underused species Brome species are known for their drought tolerance, but are not commonly used in Nordic countries, partly due to a lack of seed supply. Smooth brome (Bromus inermis) has been tested in the past, whereas less is known about Alaska brome (Bromus sitchensis). Preliminary research in Estonia (Tamm et al., 2020) compared the two species and found that Alaska brome can be higher yielding than smooth brome (Tamm et al., 2020) and tall fescue (Tamm et al., 2018) and is a good companion species to lucerne. A related species of timothy is the lesser known Boehmer's cat's-tail (Phleum phleoides). In a set of studies, Boehmer's cat's-tail had low yield, but good quality and resistance to drought stress, which makes it interesting for development through plant breeding. Another perennial grass known to be drought resilient is intermediate wheatgrass (IWG) (Thinopyrum intermedium). Studies comparing the response of several perennial grasses to deficit irrigation show that intermediate wheatgrass responded better than tall fescue to partial water deficits in dry environments (Lauriault et al., 2005; Orloff et al., 2016; Smeal et al., 2005). The drought resilience of IWG is confirmed by trials in South and Middle Sweden, which were assessed during the drought year of 2018 (Mårtensson et al., 2022). IWG is able to avoid drought through its deep root system that reaches to at least a depth of one meter (Pugliese et al., 2019; Sakiroglu et al., 2020). In addition to those already discussed, there are a range of other perennial legumes that may potentially have a high level of drought resilience. However, for these species to be useful they also need to be suitable in other aspects, not least of which is their winter hardiness, which means that the pool of possible species reduces as the area of focus moves north. Even if a potential species is able to survive the winter, they must also be able to compete in mixed swards, be resistant to local diseases, and have suitable forage quality. Species known to have drought tolerance and which can potentially be cultivated in the Nordic countries include birdsfoot trefoil (Lotus corniculatus), kura clover (Trifolium ambiguum), zig-zag clover (Trifolium medium), sainfoin (Onobrychis viciifolia), liquorice milkvetch (Astragalus glycyphyllos), cicer milkvetch (Astragalus cicer), black medic (Medicago lupulina), strawberry clover (Trifolium fragiferum) and Talish clover (Trifolium tumens) (Bender et al., 2017; Butkute et al., 2018; Elgersma et al., 2014; Parsons, 2020). Forb species of interest include salad burnet (Sanguisorba minor), caraway (Carum carvi), ribwort plantain (Plantago lanceolata), and chicory (Cichorium intybus) (Elgersma et al., 2014). These Forage plants Proceedings of the 12th Nordic Feed Science Conference 19 species are either not widely used in the Nordic countries, or little is known about their drought resilience, or both. Irrigation Irrigation is one way to compensate for a lack of water, however it is uncommon in the Nordic countries and mostly used for high value crops such as potato. The irrigable land, as a fraction of total utilized agricultural area ranges from 2.4% in Finland to 8.4% in Denmark (Eurostat, 2016). Despite the lack of irrigation in Sweden, there is abundant surface water in the form of lakes and rivers, and there is also potential to collect water on-farm through strategically located dams. For most locations in Sweden, it is likely that irrigation will remain a risk management strategy to cope with water deficits rather than a strategy used through the growing season to boost overall production. Despite the cost of irrigation in terms of investment, time, and operational expenses, more widespread use could help ruminant producers to become more resistant to drought conditions and be able to protect their valuable breeding animals. However, irrigation comes with a number of challenges, in addition to the cost. Irrigation design and management are crucial. Farmers must have access to good information about how to plan irrigation in different soil types, understand crop water requirements, and schedule irrigation. Besides the issues associated with large scale irrigation projects, even small-scale irrigation can come with potential environmental challenges, including leaching of nutrients, salinization, waterlogging, runoff reducing downstream water quality, effects on aquatic ecosystems, and impact on groundwater, including leaching of nutrients (Stockle, 2002). Recommendations Even though there are many unknowns regarding drought resilience of forages in the Nordic countries, there are practices that can help farms to become more resilient. We do not know the extent or all of the mechanisms of drought resilience in Nordic forages. However, there is ample experiential evidence that certain species such as tall fescue, cocksfoot, and lucerne are more drought resilient. In locations where rainfall is comparatively lower and drought is common, these species should be the main components of forage mixtures. In locations where drought is less common, these species should be included at a lower rate in mixtures or in selected fields. Diversity is a major source of ecological stability. In leys, diversity can be achieved by having multiple species in a sward, or by having multiple fields with different species combinations. The combination of red clover and timothy is an important mix that represents large areas of ley crops in Nordic countries. Consequently, much of the knowledge about ley management is adapted to these two species. Using the same management principles for other species will likely not lead to the same forage quality or level of persistence. For example, tall fescue may need to be harvested more frequently than timothy to achieve the same level of digestibility. Lucerne needs careful management in autumn to ensure appropriate winter hardening if it is to be persistent. Future research Although much is known about the relative differences in drought resilience of forage species, more knowledge is needed on how these species perform in Nordic conditions with different average rainfalls and soil types. The approach of Halling (2020), which used Forage plants 20 Proceedings of the 12th Nordic Feed Science Conference multiple variety trial sites, can be further explored, including longer-term comparisons and other metrics of drought resilience. Drought recovery of forages is an area where there are limited field studies. It may be possible to address recovery through long term datasets, however it would also benefit from specially designed studies with specific measurements. To better understand the drought avoidance characteristics of different species, in situ rooting depth studies are an option. This can be done with great difficulty through direct observance of roots, or indirectly through soil water monitoring equipment. The capacity to measure soil water content and crop water use will become a more important technique, particularly if irrigation becomes more widespread. Forage breeding in Nordic countries has traditionally focused on yield and winter survival. Developing robust ley production systems for the future necessitates species that can resist and recover from stresses such as cold, ice, waterlogging, and drought. Breeding for these characteristics requires the development of efficient methods for screening plants for resilience to multiple abiotic stresses. It is important that new cultivars bred for resilience to certain stresses are not inadvertently more susceptible to other stresses. The potential of new and alternative species should also not be forgotten in the quest for more resilient forages systems. References Akinroluyo, O.K., Jaskune, K., Kemesyte, V. & Statkeviciute, G., 2020. Drought stress response of Westerwolths ryegrass (Lolium multiflorum ssp. multiflorum) cultivars differing in their ploidy level. Zemdirb.-Agric. 107, 161–170. https://doi.org/10.13080/z- a.2020.107.021 Aslam, M., Maqbool, M.A. & Cengiz, R., 2015. Mechanisms of Drought Resistance, in: SpringerBriefs in Agriculture. Springer Intern. Publ., Cham, pp. 19–36. https://doi.org/10.1007/978-3-319-25442-5_3 Beillouin, D., Schauberger, B., Bastos, A., Ciais, P. & Makowski, D., 2020. Impact of extreme weather conditions on European crop production in 2018. Philos. Trans. R. Soc. B Biol. Sci. 375, 20190510. https://doi.org/10.1098/rstb.2019.0510 Bender, A., Tamm, S. & Aavola, R., 2017. Biomass allocation to shoots and roots, and nutrient content in herbage legumes. Proc. 19th Symposium Europ. 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URL https://library.wmo.int/idurl/4/35689 (accessed 3.9.24) Forage plants Proceedings of the 12th Nordic Feed Science Conference 25 Forage nutritive value of dual-use populations of Kernza Intermediate wheatgrass V. D. Picasso1,2 & K. Olugbenle1 1University of Wisconsin-Madison, Plant and Agroecosystem Sciences, Madison, WI, USA 2Swedish University of Agricultural Sciences, Crop Production Ecology, Uppsala, Sweden. Correspondence: valentin.picasso@slu.se Introduction Intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & Dewey; IWG) is a perennial cool-season grass native of Europe, used for forage, which has been recently bred for grain and marketed as Kernza in North America (Lanker et al., 2019). It is adapted to dry regions, with optimal rainfall between 300 to 750 mm, and produces well in regions up to 1150 mm of rainfall. It grows on a wide range of soils (coarse, medium, and fine-textured, with pH ranging from 5.6 to 8.4), and prefers well-drained soils, loamy to clay-textured. It is cold-tolerant and not susceptible to spring and fall freezing. It can also withstand moderate periodic flooding in the spring (Hybner & Jacobs, 2012). It can also provide multiple ecosystem services: protect soil from erosion, annual weed control (Zimbric et al., 2020), reduce nutrient leaching (Jungers et al., 2019), increase soil organic carbon and improve biota linked to high soil quality (Culman et al., 2013). Furthermore, this crop is very drought tolerant due to its deep root systems at a depth of one meter and thus contribute to increased carbon storage in the soil (Sakiroglu et al., 2020). The IWG has been introduced to Sweden and tested in several locations (Alnarp, Rådde, Lundsbrunn, Uppsala, Umeå). Preliminary forage yield from a pilot study at Rådde (Nadeau et al., 2023) showed an increase from 3100 kg DM per ha on 8 June to 7400 kg DM per ha three weeks later at one harvest. It can be 1.70 m tall at maturity in September, and the straw yield reached over 8,000 kg DM per ha at SLU in Alnarp (Dimitrova Mårtensson et al., 2022). It is also being tested in other countries in Europe (France, Finland, Norway, Lithuania, Estonia, Denmark, Poland, Belgium, Germany, and Ukraine). Growing IWG as a dual-use perennial crop provides two sources of income to farmers: forage and grain. First year forage harvest yields in the US range from 4.5 to 11.7 tons per ha in summer, and up to 3.9 tons per ha in spring and autumn (Franco et al., 2021). The forage nutritive value of IWG is high in spring and autumn harvests and are suitable for lactating beef cows, dairy cows, and growing livestock (Favre et al., 2019). Farmers let animals graze the crop in early spring, harvest it as forage early in the summer or harvest grain and use the straw at grain harvest as bedding or mixed in feed rations (Lanker et al., 2019). Intercropping legumes with IWG in mixtures increases forage quality (Pinto et al., 2023). Intermediate wheatgrass breeding programs have improved agronomic performance of the crop in monoculture systems, but no systematic evaluations of breeding lines have been done in intercropping with legumes. The objective of this study was to compare dual use IWG populations intercropped with lucerne on forage yield and quality. Materials and Methods Breeding populations from The Land Institute (KS, USA), University of Minnesota (MN, USA), and University of Manitoba, Canada, were evaluated at Arlington, Wisconsin, USA (43°18’9.47″N, 89°20’43.32″W). Intermediate wheatgrass was seeded in the autumn in a mixture with lucerne, harvested the next summer for grain and in the subsequent autumn for forage, over two years. The treatment design was a single-factor experiment with 11 breeding mailto:valentin.picasso@slu.se Forage plants 26 Proceedings of the 12th Nordic Feed Science Conference populations (2 from Canada, 4 from KS, 5 from MN). The field plot design was a completly randomized block design with 4 replications. Seeding rate was 13.5 kg ha-1 of pure live seeds (PLS) with 30.5 cm row-spacings. The plot sizes was 1.2 by 3 m. Lucerne was frost seeded at 16.8 kg ha-1 in the spring after seeding intermediate wheatgrass. Soils were Plano silt loam with 2 to 6% slope, and no fertilizer was applied. Forage was hand-harvested at the soil level with sickles, using one 50 x 50 cm quadrat to include two intermediate wheatgrass rows. Forage samples were then placed in a forced-air dryer at 52°C for at least five days. Forage quality was analyzed with wet NIRS in the UW-Madison forage quality lab. Results and Discussion The total summer forage biomass (IWG, lucerne and weeds) in the first year was not separated and there were no differences among populations (Figure 1). Mean summer forage biomass was 8565 kg ha-1 and 6650 kg ha-1 for the first and second year, respectively. Mean summer forage yield in the second year for IWG was 4554 kg ha-1 and for lucerne 1852 kg ha-1. Forage yield in the autumn harvest of the first year was 576 kg ha-1. The populations from KS had lower weed biomass in the second summer than other populations (Figure 1). Figure 1 Summer forage biomass per IWG population and harvest year. First year total forage biomass and second year biomass for IWG, Lucerne, and weeds is reported. No differences were found for total forage, IWG, or legume forage biomass. Weed biomass values with the same letter denote no statistical difference (p<0.05). The forage nutritive value of IWG in the summer after grain harvest was relatively low, comparable to wheat straw (Table 1). It must be mixed with higher quality forage for beef or dairy cattle diets. No differences were found for CP or ADF among populations, but populations differed in NDF. The quality of the mixture was similar, given that both species were past their maturity stage; no differences were found between populations. The percent of legume in the mixture in the summer averaged 29.5%. The autumn forage quality of the mixture was high (Table 1), and populations differed in CP (MN1505 was highest). Table 1 Mean (and range) of forage quality parameters (g/kg DM) for 11 Kernza intermediate wheatgrass populations intercropped with lucerne in Wisconsin (second year for summer and first year for autumn) CP ADF NDF IWG summer straw 27 (22-32) 459 (445-478) 682 (656-707) IWG+Lucerne summer 65 (52-76) 467 (456-479) 656 (634-678) IWG+Lucerne autumn 188 (178-206) 272 (243-315) 404 (355-491) Forage plants Proceedings of the 12th Nordic Feed Science Conference 27 Conclusions The different populations of Kernza intermediate wheatgrass had similar forage production and quality. Summer forage from IWG harvested after grain maturity was of high productivity but limited feed value for cattle. In contrast, the forage quality of the autumn regrowth was of adequate quality for beef and dairy. This highlights the benefits of dual use Kernza for perennial grain and forage systems. References Culman, S.W., Snapp, S.S., Ollenburger, M., Basso, B., & DeHaan, L.R., 2013. Soil and Water quality rapidly responds to the perennial grain Kernza Wheatgrass. Agron. J., 105, 735–744. Dimitrova Mårtensson, L-M., Barreiro, A., Li, S., & Steen Jensen, E., 2022. Agronomic performance, nitrogen acquisition and water-use efficiency of the perennial grain crop Thinopyrum intermedium in a monoculture and intercropped with alfalfa in Scandinavia. Agron. Sustain. Dev. 42, 21. Favre, J.R. Munoz Castiblanco, T., Combs, D.K., Wattiaux, M.A., & Picasso, V., 2019. Forage nutritive value and predicted fiber digestibility of Kernza intermediate wheatgrass in monoculture and in mixture with red clover during the first production year. Anim. Feed Sci. Technol. 258, 114298. Franco, J.G., Berti,M., Grabber,J., Hendrickson, J., Nieman, C., Pinto, P., Van Tassel, D., & Picasso, V., 2021. Ecological intensification of food production by integrating forages. Agronomy 11, 2580 Hybner, R. & Jacobs, J., 2012. Intermediate Wheatgrass (Thinopyrum intermedium L.): An Introduced Conservation Grass for Use in Montana and Wyoming. USDA. NRCS. Plant Mater. Techn. Note No. MT-80., USA. Jungers, J.B., DeHaan, L.H., Mulla, D.J., Sheaffer, C.C., & Wyse, D.L., 2019. Reduced nitrate leaching in a perennial grain crop compared to maize in the Upper Midwest, USA. Agric Ecosyst. Environ. 272, 63-73. Lanker, Bell, M. & Picasso, V., 2019. Farmer perspectives and experiences introducing the novel perennial grain Kernza intermediate wheatgrass in the US Midwest. Renew. Agric. Food Syst. 1-10. Nadeau, E. & Picasso, V., 2023. Forage Production and Nutritive Value of Kernza Intermediate Wheatgrass in Sweden. ASA-CSSA-SSSA meeting. St. Louis, MO, USA Pinto, P., Cartoni-Casamitjana, S., Cureton, C., Stevens, A.W., Stoltenberg, D.E., Zimbric, J. & Picasso, V., 2022. Intercropping legumes and intermediate wheatgrass increases forage yield, nutritive value, and profitability without reducing grain yields. Front. Sustain. Fd. Syst. 6, 977841. Sakiroglu, M., Dong, C., Hall, M.B., Jungers, J. & Picasso, V., 2020. How does nitrogen and forage harvest affect the belowground biomass and nonstructural carbohydrates in dual-use Kernza intermediate wheatgrass? Crop Sci. 60, 2562-2573. The Land Institute, 2024. New Roots international. https://landinstitute.org/our-work/new- roots-international/ Zimbric, J.W., Stoltenberg, D. & Picasso, V., 2020. Effective weed suppression in dual-use intermediate wheatgrass systems. Agron. J. 112, 2164–2175. https://landinstitute.org/our-work/new-roots-international/ https://landinstitute.org/our-work/new-roots-international/ Forage plants 28 Proceedings of the 12th Nordic Feed Science Conference Methane emission Proceedings of the 12th Nordic Feed Science Conference 29 Effects of two novel feed additives on enteric methane production of Nordic Red dairy cows J. Vattulainen1, A.R. Bayat1, T. Stefanski1, M. Rinne1 & I. Tapio2 1Natural Resources Institute Finland (Luke), Animal Nutrition, 31600 Jokioinen, Finland. 2Natural Resources Institute Finland (Luke), Genomics and Breeding, 31600 Jokioinen, Finland. Correspondence: alireza.bayat@luke.fi Introduction Ruminants with their unique ability to convert feedstuffs into high-quality products as milk and meat contribute to the food production systems. However, due to the ruminal fermentation of feed, they contribute to climate change, mainly by emitting methane (CH4), which is a potent greenhouse gas. Therefore, practical solusions need to be sought to mitigate CH4 emissions from ruminants. DiGestoChar is a commercial product based on biochar and fibrolytic enzymes that has indicated positive effects on CH4 mitigation in vitro and milk production in vivo (pers. comm; Branko Petrujkic, GoBioFarm, Iisalmi, Finland). It has been hypothesized to improve digestibility of feed via enzymes and provide optimal conditions for development of rumen anaerobic bacteria, protozoa and fungi. Calcium peroxide (CaO2) has indicated positive effects on reducing CH4 in beef cattle (Roskam at al., 2023). Oxydising agents like CaO2 can release O2 and subsequently reactive oxygen species when decomposed in the rumen which negatively affect methanogens. The release of extra O2 in such an anaerobic environment has the potential to directly inhibit methanogens. Therefore, the objective of this study was to evaluate dietary supplementation with DiGestoChar and two levels of calcium peroxide on enteric CH4 emissions, performance, and rumen fermentation of dairy cows. Materials and Methods Four multiparous Nordic Red lactating dairy cows (days in milk 58 ± 9.2, body weight 637 ± 59.3 kg, milk yield 38.4 ± 2.6 kg/day) were used in a 4 × 4 Latin square experiment, which consisted of four 28-day periods. The first 24 days of each period were used for adaptation when the cows were housed in free-stall pens with controlled individual feed bins. The cows were kept in respiration chambers for sample collection and gas exchange measurements during the four last days (Days 24-28) of each period. Experimental treatments comprised: 1) CON, a control diet based on grass silage (timothy-meadow fescue) supplemented with dietary concentrates, 2) DC, the CON diet supplemented with 0.2% DiGestoChar (GoBioFarm, Iisalmi, Finland), 3) CaPe1, the CON diet supplemented with 0.75% calcium peroxide, and 4) CaPe2, the CON diet supplemented with 1.5% calcium peroxide. The diets were balanced based on Luke (2024) recommendations and were fed as total mixed rations with forage to concentrate ratio of 65:35 for CON and DC diets. However, to balance Ca:P ratio in CaPe1 and CaPe2 diets, forage to cocentrate ratios were marginally compromised. Sugar beet pulp and rapeseed meal were kept constant in the diets to avoid any confounding effect from palatability and crude protein concentration with the treatment effect, respectively. The cows were fed four times a day at 7:00, 13:00, 17:00 and 19:00 h. Milking was done twice a day at 07:00 and 17:00 h. Silage and concentrate samples were taken on Days 24 and 26 during each sampling period. Daily feed intake and milk yield recorded between Days 24 and 28 of each period were used for statistical analysis. Milk was sampled in 6 consequative mailto:alireza.bayat@luke.fi Methane emission 30 Proceedings of the 12th Nordic Feed Science Conference milkings and the samples were analyzed separately for fat, protein, lactose, urea and somatic cells (MilkoScan FT6000, Foss Electric, Hillerød, Denmark). Energy corrected milk (ECM) yield was calculated according to Sjaunja et al. (1990). Four open-circuit respiratory chambers wer